If one were to definitively name the golden age of the guitar riff, it'd be tough to argue against the ‘70s, when the lean rock ‘n' roll of the late ‘60s met the rise of heavy metal. Led Zeppelin sculpted goliath hooks that pushed their blues sound into the cosmos, and Black Sabbath, armed with a dark and towering din, struck fear into the hearts of parents around the world. Whether employing turbocharged takes on classic forms (AC/DC), building arena-crumbling walls of sound (The Who), or embarking on interstellar prog missions (Rush), the riff rose to glorious heights in the hands of these artists.